Piston



Feb. 26 1924.

H. J. HATER PISTON Filed April 24 1922 Patented Feb. 26, 1924.

HARRY J. HATER, OF CINCINNATI, OHIO.

PISTON.

Application filed April 24, 1922. Serial No. 556,234.

To all whom it may concern:

Be it known that I, HARRY J. HATER, a citizen of the United States of America, re-

siding at Cincinnati, in the county of Hamilcation.

My invention relates to pistons, and especially to pistons used in internal combustion engines. My piston is of the wellknown type having a solid head from which a depending skirt extends.

An object of my invention is the construction of a piston which will fit efficiently in the cylinder of an engine under all conditions.

A further object of my invention is the construction of a piston which, while subject to expansion and contraction, will not warp, will not cave in, and will-notknock in the cylinder.

A still further object of my invention is the construction of a piston which will properly lubricate the walls of the cylinder.

A still further object is the construction of a piston which will not score the cylinder walls as a result of the expansion of the piston pin bearings. s

Figure 1 is a side elevation of a piston made in accordance with my invention;

Figure 2 is a side elevation with the piston turned 180 from the position shown in Figure 1; Figure 3 is a side elevation with the piston turned 90 from the position shown in Figure 1; and' Figure 4 is a transverse section on the line 4- 1 of Figure 3. v

A piston designated as a whole by 1 has a solid head 2 and a depending hollow skirt portion 3. The head has the usualpiston ring grooves 4. The head below the lower groove is slightly beveled (shown accentuated in the drawing) at 5 to enable the oil which may reach this part of the head to drain back through the relief oil holes and the transverse slit. The metal of the skirt portion is cut away at 6 around the piston pin opening 7. This cut-awaypart 6 is keystone shaped. Four oil holes 8 are spaced around each piston pin opening within the keystone relief. Extending from just inside one keystone relief is a transverse cut or slit 9 through the skirt which extends to just inside the opposite keystone relief. The same kind of a transverse slit 10 is on the opposite side of the piston.

On the side of the piston which receives the thrust on the power stroke a slit 11 is made at an angle to the vertical, the slit beginning a' short distance from thetransverse slit and extendingto the bottom of the piston skirt, the lower end of the slit being shown about in line with the oil holes. The skirt portion of the piston has a band 12 around the inside of the skirt about half way between the lower part of the piston pin opening and the bottom of the-skirt. The slit or cut 11 does not extend through the band 12, as is clearly indicated at 13. In.- stead of the skirt portion of the piston shown in Figure 1 consisting of resilient parts, which would be the case if the slit 11 were cut through the band 12 and if that slit were cut through to the'transverse slit 9, the skirt portion does consist, as shown in Figure 1, of a side wall made by the uncut portion between the upper end of the diagonal slit and the uncut band 12.

On the piston skirt portion, as shown in Figure 2, a slit 14 extends from the transverse slit diagonally to the bottom of the that the best results are obtained in the construction of a'piston if the piston skirt on the side of the piston which receives the thrust on thepower stroke has, in addition to a. transverse slit, a slit extending from a point adjacent to the transverse slit to the bottom of the skirt but with the slit not cut through the entire skirt at some point intermediate the end of the slit. In the form of piston disclosed, the ring 12 is not cut through. There are, therefore, resilient parts belowthis uncut band. This construction gives the necessary resiliency to the skirt, but prevents the parts from caving in or being pushed outward. The uncut band prevents undue expansion and contraction of the skirt-on the thrust side. The two slits provide for lubrication by causing the distribution of oil over the surface of the piston thereby reducing friction especially on the thrust side of the piston and take care of the expansion and contraction of the skirt and the cylinder. 1 Oil is also supplied by the slits to'the relief, thereby lubricating that portion of the piston directly beneath the wrist pin hole and also the wrist pin bearing surface. This construction of the skirt on the side of the piston which receives the thrust on the power stroke prevents destruction or injury of the piston and the cylinder and produces in combination with the parts on the opposite side of the piston a perfect acting piston.- I

The keystone-shaped relief has several purposes. Among these are to drain back to its source all oil not necessary for lubrication which reaches the relief, and to allow for expansion of the piston due to the conventional heavy piston pin bosses, not shown. It is evident thatvthe diagonally placed sides of the keystone relief prevent scoring of the cylinder which might result if the sides were parallel with the vertical axis of the piston. The holes in the lower part 7 of the relief drain oil back into the crank case keeping the oil in circulation.

The bevel of the head below the lower piston ring groove serves the purpose of efficiently draining the oil back to its source.

While my piston may be made of any suitable material, it is efficiently made from aluminum or aluminum alloy.

While the diagonal slits are shown at about an angle of 45 to the vertical, I do not limit myself to that angle, nor to the specific kind of slit shown.

The side of my piston which receives the thrust on the power stroke may be indicated in any suitable way on the top of the piston or on any other suitable portion thereof. It is understood that the side of the piston on which the diagonal slit is not cut through is placed to receive the thrust on the power stroke.

The invention of the keystone shaped relief has been claimed in divisional application No. 67 6,344, filed November 22, 1923.

Having described my invention, what I claim as new and desire to protect by Let ters Patent is l. A piston comprising a head and a depending skirt, said skirt having a transverse slit therein and said skirt having a diagonal slit therein extending from the bottom of said skirt and terminating before it reaches the transverse slit and without connection therewith, said skirt being incompletely cut through by said slit at a point spaced from both ends of said diagonal slit. 7

2. A piston comprising a head and a skirt, said skirt having transverse slits on opposite sides thereof and having a diagonal slit on one side thereof extending from. the bottom of said skirt and terminating before it reaches a transverse slit and without connection therewith said skirt being incompletely cut through by said diagonal slit at a point spaced from both ends of said diagonal slit and having a. diagonal slit on the other side thereof, extending from the bottom of said skirt to a transverse slit.

In testimony whereof I afiix my signature.

HARRY J. HATE-R. 

